CROWES NeoBird1-060726.qxp 2/8/06 2:41 pm Page 42 >> IDENTIFICATION WORKSHOP MANTLED HAWK Field identification of Mantled Hawk Leucopternis polionotus Sergio H. Seipke, Douglas Kajiwara and Jorge B. L. Albuquerque antled Hawk Leucopternis polionotus is a photographs and video taken in the wild. Adults largish buteonine considered Near were studied on more than 20 occasions at MThreatened3 that inhabits humid forests, Urubici, Santa Catarina, Brazil, in July 2003 and second growth and Paraná Pine Araucaria June 2006, and a juvenile was observed, by DK, at angustifolia mixed woodland, from sea level to at General Carneiro, Paraná, Brazil, on 25 May 2003. least 1,500 m, recorded from Alagoas to Rio I. Accordi recorded bare-parts coloration for three Grande do Sul in eastern and southern Brazil20, wild individuals, two adults and one of unknown north-east Argentina6,16, east Paraguay5,8 and, age, in Rio Grande do Sul, Brazil, and G. S. perhaps, northern Uruguay10. However, there are Cabanne photographed an adult held at São Paulo no documented records from Argentina, Uruguay zoo, Brazil. Though we have studied specimens, or Paraguay. Of four sight records in north-east we report only plumage details observable in the Argentina since 197514, one involved a field. We also provide information to distinguish misidentified pair of White-tailed Hawks Buteo other raptors sympatric with Mantled Hawk. albicaudatus (C. Saibene pers. comm.) and no published details are available for the others. One was reportedly observed along the lower río Descriptions Carapá, eastern Paraguay9 in 1989, but no details Perched adult (Plate 1, Figs. 1d,f,g; 3) Appears were given. chunky, with broad ‘shoulders’ relative to total The species reportedly replaces White-necked length. White head looks large, round and Hawk L. lacernulatus above 500 m1,2,5,8,13, but conspicuous; markings around eyes afford a Mantled Hawks are observed from sea level, and masked appearance. Cere and lores ash-grey to White-necked Hawks have been seen as high as dull yellow; bill has paler grey base grading to 900 m (R. Fadini & R. Parrini pers. comm.; SHS & black at tip. Irides brown in good light, otherwise DK pers. obs.). Habitat use and relative abundance appear black. Underparts unmarked white. along altitudinal gradients are poorly understood Mantle, scapulars and tertials slaty grey with for Mantled Hawk. broad white tips affording a somewhat scaled Though several field guides depict and pattern. Slate-black upperwing-coverts appear describe this hawk, none of these permits swift darker than scapulars. Secondaries dark lead grey and confident identification in the field, and some with 3–4 narrow darker bands (in good views) and are inaccurate in iris and facial skin coloration, broad white tips form a shallow U if seen from relative proportions, the position of the wingtips behind. Secondaries reach halfway to tail tip, relative to the tail tip, and flight silhouette. concealing rump and base of tail. Primaries black Accurate field identification is necessary to with greyer bases and thin white tips reach or produce better information on its distribution, slightly exceed tail tip, sometimes forming a small ecology and habitat requirements, which in turn dark triangle below tail. Usually only the white are required to develop an appropriate part of the tail is visible, but in some individuals conservation strategy4. one, rarely two, dark bands are just visible at the tail base. Tail tip square. Tarsi yellow and usually partially concealed; toes strong and orangish Methods yellow. Plumage descriptions, illustrations and behavioural patterns reported here are from field Perched juvenile (Plate 1, Fig. 1e) Very much like observations, careful notes taken while observing adult but dark streaks on crown and nape visible birds through binoculars and telescopes, and at distance. Upperwing-coverts fringed whitish. 42 Neotropical Birding 2006 CROWES NeoBird1-060726.qxp 1/8/06 2:16 pm Page 43 Cere whitish to dull yellow. Somewhat marbled 1, Figs. 1a–b). Note, dark tail base seldom visible. dark bars at base of tail more numerous and Note ill-defined two-toned underwing pattern and noticeable than in adults. white leading edge to wings. Wings held either level, on a shallow dihedral, or slightly cupped Flying birds (Plate 1, Figs. 1a,b; 4) Very unique (Plate 1, Figs. 1c, 4). silhouette with long, very broad, rounded wings and short tail. White head appears bulky and Perched White square tail and white U formed sometimes (in females?) projects further than tail. by secondary tips unique and eliminate other Wings longer than body and tail-length in soaring raptors. Wingtips reach or slightly exceed tail tip birds (wingspan 2.6˘ total length). Broad white (Fig. 3). White tips to dorsal feathers very trailing edge to wings conspicuous in good light noticeable and make birds, especially juveniles, (especially if backlit, but not obvious in cloudy appear scaled from behind (Plate 1, Figs. 1d–e). conditions). All-white tail appears squarish if Front on, look for the white tail (Plate 1, Fig. 1g). folded, slightly wedged when partially fanned, and These field marks are noticeable at long distance rounded when fully fanned. Dark base of tail and suffice to separate all sympatric raptors, seldom noticeable. Seen from behind or if tail fully perched or in flight. fanned, wings and tail form continuous trailing edge. Dark distal half of remiges contrasts with rest of underside, but border ill-defined, especially Similar species on secondaries. Leading edge to wings noticeably Several other ‘black-and-white’ raptors in south- white. Legs not very apparent. east Brazil, north-east Argentina and eastern Paraguay could be confused with Mantled Hawk. Behaviour Perches on exposed branches or bare Silhouette shape, and tail and trailing edge snags in upper half of living trees, but also on dead coloration are the most important characters to ones15 (I. Roesler pers. comm.). In hilly areas, we note in flying birds, whereas tail and secondary tip usually found it on the upper half of forested coloration should be noted in perched birds. slopes. Perches quite straight with tarsi barely White-necked Hawk (Plate 1, Figs. 2a, 5, 6) is visible. Tail often held vertical or slightly forwards. not always easily separated from Mantled Hawk Soars in circles, usually on level wings—but might and is sympatric at several localities5,8,10,13. This hold wings above the horizontal in full soar— species also perches exposed on conspicuous frequently and for long periods, low over forest or, perches and soars above the forest like Mantled mostly, high from mid morning until late Hawk. The white head, dark dorsum, mainly white afternoon. Once height attained, usually glides tail and rounded wings make it overall similar to long distances on somewhat ‘cupped’ wings. Long Mantled Hawk. In flight White-necked Hawk is broad wings give species a very conspicuous flight relatively shorter winged and has a noticeable as birds seem to float in midair. Flapping shallow black subterminal band on the longer tail (Plate 1, and ‘flexible.’ Birds flap very infrequently when Figs. 2a, 6). It soars with wings held above the soaring. One was observed hunting a lizard horizontal (dihedral) resembling a pale-morph (15–20-cm long) from a perch; the bird glided and adult Variable Hawk Buteo polyosoma. The white caught it on the ground, immediately passed the head projects less from the body than the tail. prey to the bill, then took off and soared in wide Though the underwing pattern is two-toned, as in circles; the prey was consumed on the wing, Mantled Hawk, the dark terminal band to the before perching and still-hunting again. We secondaries is well defined, forming a dark (not observed flocks of Chopi Blackbird Gnorimopsar white) trailing edge to the wing. The dorsal chopi, Golden-winged Cacique Cacicus surface lacks the white U on the secondaries in chrysopterus and Epaulet Oriole Icterus perched birds. The whitish bases (not tips) to the cayennensis near to hawks, even on the same mantle, back and scapulars make them appear perch, without mobbing or chasing the raptor. blotched (rather than scaled) from behind; tertials are dark-tipped. White-necked Hawks might also show a masked appearance, but lores are whitish Field marks and other useful characters or creamy, the cere and gape dull yellow, resulting In flight Look for the broad, white trailing edge in an overall paler face pattern. Wingtips fall short to the wings and tail (Plate 1, Figs. 1a, 4), which of tail tip when perched. The dark bands at the appears translucent against the sun. Long base of the undertail are usually concealed by the secondaries make the tail appear very short (Plate long coverts in perched birds, and not easy to Neotropical Birding 2006 43 CROWES NeoBird1-060726.qxp 1/8/06 2:16 pm Page 44 Plate 1. Mantled Hawk Leucopternis polionotus (1) in Figure 1d. Perched adult (yellowish cere). White head comparison to adult White-necked Hawk L. lacernulatus and neck conspicuous. Chunky body. Secondary tips (2) (not to scale). Arrowheads denote important field reach halfway to tail tip and form noticeable white U. marks, long arrows subsidiary characters useful in the Note white tips to body feathers on dorsal surface. field (Aldo Chiappe) Primaries reach or slightly exceed tail tip. Dark base of Figure 1a. Soaring bird against blue sky. Short all-white white tail seldom visible. tail and white trailing edge to wings diagnostic. Short Figure 1e. Juvenile. Upperwing-coverts fringed buff or tail barely projects beyond trailing edge to wings. whitish. Bands on tail base noticeable. Note dark Greyish parts to remiges somewhat contrast with rest of streaks on top of head and lower hindneck.